Discharge mechanism and fail-safe for hydraulic classifiers



E. P. THAMME Aug. 8, 1967 DISCHARGE MECHANISM AND FAIL-SAFE FOR HYDRAULIC CLASSIFIERS 5 Sheets-Sheet l INVENTOR Eric P; Gifim&

lll lllllll II Filed Feb. 6, 1964 E. P. THAMME Aug. 8, 1967 DISCHARGE MECHANISM AND FAIL--SAFE FOR HYDRAULIC CLASSIFIERS 3 Sheets-Sheet 2 Filed Feb.

INVENTOR Eric P. Thamme E. P. THAMME Aug. 8, 1967 DISCHARGE MECHANISM AND FAIL-SAFE FOR HYDRAULIC CLASSIFIERS 3 Sheets-Sheet 15 Filed Feb. 6, 1964 FIGJO INVENTOR ENC P. Thamme United States .Patent 3,334,742 DISCHARGE MECHANISM AND FAIL-SAFE FOR HYDRAULIC CLASSIFIERS Eric P. Thamme, 58 Clinton St., Fanningdale, N.Y. 11735 Filed Feb. 6, 1964, Ser. No. 343,055 19 Claims. (Cl. 209-162) This invention relates generally to material-actuated control devices in connection with hydraulic classifiers, and his related to my patents, No. 2,865,503, No. 2,999,- 594, and No. 3,077,265. Patent No. 2,999,594 discloses a discharge mechanism which is responsive to a variably impeding material level in conjunction with an operatively induced diflerence in heads of two separately maintained bodies of water.

This application refers, in particular, to a simplification of the auxiliary water control disclosed in Patent No. 2,999,594; to inclined conduit and umbrella means as providing operational advantages in connection therewith; and to an auxiliary control mechanism, or fail-safe, ancillary to material-actuated control devices, generally.

The proper functioning of the discharge mechanism shown in Patent No. 2,999,594 is described therein as being related to the formation of and the confining of an accruing head-differential within desirable limits. Auxiliary means provided to maintain these limits include a valved inlet, a float supporting said valve, and an auxiliary float chamber. It is a purpose of this invention to create equally favorable conditions by simpler means.

The provisioning of adequate space to suitably distribute sand and water is essential to the proper functioning of the referred to discharge mechanism, and is realized to best advantage when conduit or umbrella means are independently or jointly inclined to thereby provide virtually separate passages for media of different specific gravity, and is a further object of this invention.

An additional purpose thereof is to provide an automatically intercepting fail-safe, or auxiliary control mechanism, in complementary association with an operatively independent valving mechanism.

The principal object of my invention is to provide a simply constructed and eflicient discharge mechanism, effective over a wide range of application under varying cOnditions material-actuated, and responsive to material level variations of diverse classifying apparatus.

Other objects of my invention will be apparent in the following specification and claims. The apparatus of the present invention is briefly characterized as follows.

A variably restrictive passage, and three communicably related zones are jointly disposed relative to a critical elevation which coincides with the lower edge of modified partition means, variously comprised of disjunctive, apertured, and partial partitions.

Such means, hereinafter called umbrella means, are provided in association with a vertically oriented passage to establish below said umbrella means an inter-mediately disposed distribution zone, so called inasmuch as fluid, entrained solids, and adjacently reposing solids are selectively placed and distributed therein, as well as adjacently thereto.

In the accompanying drawings, forming a part of this specification, and inwhich like numerals are employed to designate like parts throughout the same,

FIGURE 1 is a vertical, perspective View of my device, comprised of the discharge mechanism embodied in a tank, and the complementary gatetype fail-safe;

FIGURE 2 illustrates an alternate construction of the valve control mechanism;

FIGURES 3 and 4 represent alternate designs of the valve control housing;

FIGURE 5 is a diflerent species of my invention;

FIGURES 6 and 7 show a modified discharge valve;

FIGURES 8 to 10 are various views of a sleeve type fail-safe complementarily associated with a valve moving with the underflow; and

FIGURE 11 is an alternate construction of the gate type fail-safe illustrated in FIGURE 1, and is shown associated with an externally controlled species of my invention.

In the drawings, wherein for purposes of illustration are shown preferred embodiments of my invention, the numeral 10 designates a settling tank having upper and lower ends, and being comprised of upper and lower portions, for classifying and recovery purposes, respectively. Feed enters the tank from a higher elevation by chute 11, shown in FIGURE 1, of which this description is specific. Waste water overflows into the launder 12. The settled solids discharge through the underflow outlet 13 at the bottom of the tank 10. Valve 14 is seated against the outlet 13 by the valve stem or rod 15', which extends upwardly through the tank 10 to above the top of same. Connected to valve rod 15 by fulcrumed lever, or by an alternate system of levers, is the float 16. Float 16 is free to move up and down in the float chamber 17.

The float chamber is located on the side of the tank Iii, where it extends above the water table, or upper edge of the tank. A float chamber, if desired, may be located within a tank. Outside-of-tank location is not essential; it is preferred as a relatively large volume of water and a longer scalping path come into being by locating a float chamber outside of a tank, and as shown in FIGURE 1. In connection therewith it is essential to incline the sloping bottom 29 of the float chamber 17 at the angle of repose for the material, at least, to thus provide conjunctively with the opening 28 a downwardly inclined passageway for the settled solids to return by gravity from the float chamber 17 to the tank 10. Communication between the tank 10 and the float chamber 17 is provided by the opening 28, which is extended vertically in View of the simultaneous presence of a lighter and a heavier medium. The float chamber is being drained through the drain pipe 18, welded to the bottom of the extension 19, and is extending upwardly therefrom to locate the drain mouth at a suitable elevation below the water table.

The umbrella 20 is positioned intermediate of upper and lower ends of the tank 10, and is fastened to the walls thereof for its support. It is not essential to incline an umbrella. It may be positioned horizontally, or nearly so, if it is desired to revise the ratio between retained and wasted fines of that fraction of the solids input which locates reasonably close to the vertical extension 21. For reasons related thereto it may be desirable to not extend an umbrella across the entire width of the tank. The outline or shape of an umbrella may be varied considerably to meet sructural or functional requirements.

An umbrella is considered to have a preferably flat surface or platform, an edge defining the extremities thereof, a vertically positioned flange or extension, an underside and a lower edge. An umbrella is considered to be normally disposed when space below thereof is inaccessible to freely settling solids, and open space below thereof is providing a distribution zone. This zone being located immediately adjacent to the underside of said umbrella means, and being disposed intermediate thereof and the surface of the solids reposing therebelow.

A float chamber is, broadly considered, to be a suitably expanded conduit between the lower edge of an umbrella and the mouth of a drain at a higher elevation than said lower edge. It is extended upwardly to above said drain mouth, and is suitably expanded to accept an adequately sized float. One end of this expanded conduit being disposed above the surface of the umbrella; the other end thereof being disposed below the said surface. If an externally located float chamber is considered to be independent and separately positioned it may be defined as being suitably extended downwardly by a conduit to position one end thereof below the umbrella surface, and the other end above thereof.

Inasmuch as umbrella means and communication means must be conjunctively provided, a sloping conduit will be required in connection with a substantially horizontal umbrella. The conduit must penetrate the umbrella, and must be inclined at the angle of repose for the material, or in excess thereof. A conduit extending the suitably sloping float chamber bottom provided it is terminated above the highest attainable elevation of the surface of the solids reposing directly below the umbrella, is providing a self-clearing passageway for the returning solids, comprising the heavier medium, and is affording an upwardly inclined course for the lighter medium.

Three communicably related zones, an upper classifying zone 24, a lower recovery zone 25, and a substantially intermediately positioned distribution zone 26 are jointly disposed relative to one elevation. This elevation coincides with the lower edge 22 of the umbrella 20. The recovery zone 25 extends between the bottom of the tank 10, and the horizontal plane of the edge 22, broadly considered. The classifying zone 24 is extending between said plane, and the water table of tank 10. The distribution zone 26, disposed intermediate of the aforementioned zones, is comprised of the space 26 below the umbrella 20, and is extending vertically with the distance from the edge 22. Inasmuch as settled material reposes adjacent to the edge 22, and is sloping downwardly therefrom, this distribution zone is comprised in its entirety of the space between the operatively variable surface of the material below the umbrella, and the underside thereof. These three zones are in open communication with one another and adjoin one another in the plane of the edge 22. Pipe 27 is a vent and pressure relief.

Virtually two passages, inclined in the direction of flow, and for two media of different specific gravity are thus provided, one above the other. An upwardly inclining passage or course for the lighter medium, water and such solids as are entrained therein, is provided against the underside of the umbrella 20. It is comprised partially of the open space between the lower edge 22 and the opening 28, and partially of-the space between said opening and the mouth of the drain pipe 18 at a higher elevation. A downwardly slanting passage for the heavier medium is provided by the sloping bottom 29 of the float chamber 17. Solids settled therewithin return by gravity to tank 10.

Auxiliary means of communication are additionally provided to limit an accruing head-differential. The admission of water into the float chamber 17 through the auxiliary inlet 30 is brought about by the lowering of the float 16, and is related thereto. The auxiliary valve element 31 is fastened to suitably flexing means 32, such as nylon cord, and is' connected thereby to the outer end of the fulcrumed lever 33. A hole in the web of the channel 35 provides the passage 36 for such means. Lever 33 is fulcrumed at 37, and is pivotally connected by pin 38 in the forked end of the bracket 39, which is fastened to the float 16.

At the top of the tank, channel 35 rests against the upper edge thereof. It may be fastened thereto, but is not so shown. A vertical pipe 40 is fastened at its upper end to the channel 35, and thus furnishes a bearing and support for the valve rod 15. At its lower end is a valve-seal housing 41, which contains the seal 42, see FIGURE 3. The seal 42 and pipe 40 prevents sand from interfering with the free movement of the valve rod 15. An alternate construction accomplishing the same purpose, and providing additional advantages, is shown in FIGURE 4. The seal housing 41 is replaced by the removably secured fitting 42, having the orifice 43. The seal housing now provides a closure and a stop at the upper end of the pipe 40. A feeder pipe 44 branches from pipe 40 conveniently near the top, and conveys independently supplied water, regulated by valve 45, through the pipe 40 to fitting 42, there to establish a hydraulic seal. The spent water reduces the friction that must be overcome by lubricating the valve 14.

Above the upper end of pipe 40, valve rod 15 engages the stop plate 46. The latter is a welded assembly, comprised of the tubular member 47, the disk 46, and the pins 48 secured thereto and extending therefrom. Stop plate 46 is adjustably fastened to the valve rod 15 by suitable means, Such as set screw 49. The pins 48 engage the forked end of the lever 50, fulcrumed at 51. Brackets 52 are welded to the channel 35 to provide support for the pin 51. The above described connecting means are associated with a valve moving against the underflow.

An alternate linking mechanism is shown in FIGURE 2. The alternate modification of the connecting means is associated with a valve moving with the underflow, and is preferred for certain applications. In connection therewith, the forked end oflever 50 is extended past valve rod 15 to engage an assembly providing the second fulcrum, consisting of brackets 53, the reversing levers 54, connecting members 55, and the required pins. Either of these connecting means may be employed at will.

In FIGURE 5 is shown a species of my invention, which has what I have called an inverted umbrella so called, for the reason that the relative positions of the passage, and that of the umbrella have been inverted. To locate the communication providing opening 28 below the surface of the inverted umbrella 20 in FIGURE 5 the float chamber 17 is extended by the conduit 17'. Thus is provided an upwardly inclined course and a passage with respect to liquid communication between the tank 10 and the float chamber 17. The sloping bottom 29 of the float chamber and that of the conduit 17 conjunctively provide the downwardly inclined passageway for the heavier medium.

The structure of FIGURE 5 differs from that of FIG- URE 1 in that within a limited area of accumulation at the bottom of an operatively forming crater settled solids locate at a higher and presumably more uniform rate. An inverted umbrella in association with a co-axially positioned underflow outlet provides a relatively deep recovery zone, relatively high compression, and minimizes the losing of control water into the outgoing underflow. By control water is meant the independently existing body of water intermediate of the lower edge 22 and the fluid level in the float chamber 17.

Outside-of-tank location of a float chamber was previously pointed out as not essential in connection with FIGURE 1, and applies also to the'structure shown in FIGURE 5, as well as therewith tendered comment with respect to particle retention being partially related to umbrella positioning, inclination thereof, respectively.

All material-actuated control devices are subject to occasional malfunctioning. Interruption of malfunctioning for a predetermined length of time, provided such action is automatically terminated, is equivalent to restoration of normalcy. During this time suspended solids settle, and hanging accumulations'of solids break up, to resettle as one mass above the outlet, provided adequate duration is occasioned.

The above concept, assuming the outlet to be a suitably dimensioned orifice, may be utilized to safely discharge settling tank content. In connection with a material-actuated valving mechanism this concept is realized as an auxiliary control effectuating continuously dependable operation of the former.

Insofar as satisfactory performance of a material-actuated valving mechanism is in large measure dependent on reasonably constant input rates, and as overloads and surges are, however, frequently encountered, continuously dependable operation under these conditions is in view thereof at least partially dependent on auxiliary controls.

Higher than usual throughput rates may be tolerated in the presence of a fail-safe without incurring operational penalties, such as loss of saleable material into the waste overflow or uncontrolled and disruptive malfunctioning. Avoidance of these operational penalties confers evident advantages. Two species of fail-safe are illustrated herewith. The vgate type fail-safe is suitable for valves seating against the upper or the lower face of an outlet. This type is shown connected to, and conjunctively with, the classifier shown in FIGURE 1. A sleeve type fail-safe is shown in FIGURES 8, 9, and 10. Both types are responsive to relatively liquid underflow, and are complementary to material-actuated valving mechanisms controlling relatively dry underflow.

The gate type fail-safe shown in FIGURE 1 is fastened to the bottom of the tank 10, where it encloses the outlet 13. The sloping bottom of duct 56 extends beyond the sides of same to provide a stop or second seat 57. Bell crank 58-60, being fulcrumed at 59, connects a counterweight 61, and a hopper or receptacle 62. The hopper is positioned ahead of and below the open end of the duct 56 to provide therebetween a passage 65 for the regularly discharging underflow. Welded to the back of duct 56, which is fastened to the bottom of the tank 10, are the brackets 68 to provide bearing support for the pin 59, and thereby the fulcrum for the bell crank 58-60. The structure thereof is comprised of the dual bell cranks 58-60, and such cross members as gate 63, bar 63' and the pin 59. Several holes, not shown, may be provided near the outer end of the arm 58 to adjustably suspend therefrom the hopper 62 by the rod 66. The counterweight 61 is adjustably secured to the arm 60, and positions the hopper 62 and the gate 63 in the normally open position.

Increasingly liquid underflow, a characteristic of approaching malfunctioning, trajects beyond the passage 65 into the hopper. The near edge of the hopper 62 represents a pre-detennined limit and is related to the trajectory path of the normally discharging underflow. Excessive discharge of underflow trajects beyond this limit into said hopper. The extra weight lowers the gate 63 against the stop and second seat 57, and intercepts thereby the uncontrolled discharging of tank content for a predetermined and variable length of time which varies with the size of the hopper outlet 67.

The sleeve type fail-safe shown in FIGURES 8-10 requires an oversized valve to thereby provide a seat for the sleeve 71. This type is preferably operated with an open-ended cylindrical ring, mounted concentrically with and fastened to valve or stem to suitably confine the normal discharge, see FIGURES 6 and 7. The upper edge of the cylindrical ring 14 establishes a radially extending and fixed upper limit relative to the variably positioning valve 14, and is identical with the upper limit of a downwardly therefrom extending operational range with respect to normal discharge. Excessive discharge of under flow trajects above and beyond this limit as the trajectory path flattens out due to increasing liquidity. By being suitably confined and transitorily retained within an annular passage which is part of the fail-safe proper, accumulating underfiow effects interception by it weight. The cylindrical ring 14' is not essential to the operation of the sleeve type fail-safe shown in FIGURES 8-10; it prolongs the life of the fail-safe by preventing abrasive deterioration of the open-ended cylinder 75, and provides better control.

An annular receptacle 73 surrounds the sleeve 71 and is fastened thereto by the top cover 72. The outer cylindrical shell 73 is welded to the cover 72 and to the sloping bottom 76 to provide, cross-sectionally viewed, one highest elevation and two lowest points. The bottom secures and connects the inner open-ended cylinder 75 to the outer shell. The upper edge of the cylinder 75 provides a pro-determined limit. The horizontal plane of this upper edge must be located somewhat below the lowest attainable elevation of the valve 14. A passage 74 for the normally discharging underflow is provided through the coaxially positioned and open-ended cylinder 75.

An annular passage for the excessively discharging underflow is jointly comprised of the inner cylinder 75, the outer cylinder 73, the sloping bottom 76 therebetween, and the openings 77 in the outer shell to expose the slanting bottom at its lowest points. Vertically adjustable covers 78 are provided to regulate the duration of the interception by varying the effective area of the said openings.

The above described assembly is pivotally suspended by the hangers 79 and the pins 80 through the U-shaped ends of the lever 81, fulcrumed at 82. Pin 82 connects the two arms of the forked end of lever 81 and turns within the pipe 83. Pipe 83 provides bearing support for the assembly, and is positionally secured by the brackets 84. Counterweight 85 elevates the assembly against bolts securing the flanged pipe 70. For valves moving with the underflow, such as the valve 14 shown in FIGURE 9, and the same valve shown modified in FIGURES 67, the alternate linking mechanism applies, and is shown in FIGURE 2.

FIGURE 11 shows a modified gate type fail-safe in connection with an exterior valve control 15, which is extending suitably to above the top of the tank 10. The upper end of rod 15 must be modified by an eye, and about as the lower end thereof is shown, to engage a suitably lengthened lever 50, see FIGURE 1. The forked end of the lever 50, having been relocated at the far end of the now lengthened lever 50, and having been narrowed, is now extending beyond the far wall of the tank 10, and is there engaging the modified upper end of the extended rod 15. The lower end thereof is adapted to pivotally engage the outwardly extending arm of the bell crank 15; the downwardly extended arm thereof is fastened to the valve 14. A pair of brackets 90 and the pin 91 provide support and the pivot for the bell crank 15'. The latter is secured intermediate of the rod 15 and the outside of the tank 10, to which the brackets 90 are welded. A serviceable seat for the bell cranked valve 14 is provided by pipe 13'. Egress through the outlet 13 in the bottom of the tank 10 is governed by the valve control 15. A lowering float will move the valve control rod 15 counter thereto, and will accordingly open the valve 14.

The operation of my invention, being the same in all instances, will be described with particular reference to FIGURE 1; minor deviations will be explained hereafter. The float-valve-assembly of a classifier operating with a fail-safe need not be manually elevated to close the outlet 13. Customarily, water is delivered at first, usually at a rate far in excess of the rate required for a classifier so equipped to be self-closing. The fail-safe closes and opens intermittently until the water table in the tank 10 is high enough to elevate the float 16. Float 16 seats valve 14 against the outlet 13. Water overflows into the launder 12 and conveys such fines as are entrained therein to waste, or to a second unit for further classifying.

The retained solids settle momentarily and accumulate above the outlet 13. Simultaneously, Water drains through the pipe 18 in the float chamber 17. A rising material level in the tank 10, on having attained the elevation of the lower edge 22 of umbrella 20, interferes with the flow of water into the float chamber 17. A varying head-differential comes into being. Under influence thereof a forming sand seal collapses repeatedly during the early stages of its formation, which involves the selective distribution of solids on either side of the extension 21, and

the formation of a rapidly dissipating current. Entrained solids thus returned collectively repose directly below the opening 28. The upper layers of these and other solids reposing below the umbrella 20 are deprived of support when the outgoing material moves to lower levels, whereby the volume of the space 26 below the umbrella remains reasonably constant. Co-existence of impedance and effluence lowers the fluid level in the float chamber 17 variably. The float-valve-assembly 15 variably positions relative thereto, and accordingly causes sand to-be discharged through the outlet 13.

The control valve 15 variably lowers, and variably recovers as impedance and density of the sand seal increase and decrease, respectively. The admission of extra water through the auxiliary inlet 30 is dependent on a predetermined, and previously attained elevation of the control valve 15. Admission of extra water is provided to automatically minimize an undesirably high head-differential, when control water is being lost into the underflow, and until water enters again through the distribution zone 26, into the float chamber 17.

An impeding sand seal is operatively inseparable from the concurrently prevailing density of the suspension above the seal. A rising, or a lowering material level is necessarily expressive also of the density of the suspension above the settled solids. Ultimately, a variably lowering fluid level in the float chamber 17 is indicative of a seal variably comprised of settled and suspended solids.

The float-valve-assembly 15 is not exclusively responsive to fluid level variations in the float chamber 17. It responds to fluid level variations in conjunction with varying loads against the valve 14. These varying loads are believed to be due to variations of the material level and to therewith associated variations of the density of the suspension above the said material level.

The species of my invention shown in FIGURE has a vertically extending seal above a limited area of accumulation which is comprised of a cylindrical section of high est attainable density and is subjected to a uniformly distributed down-pull and an outwardly directed pressure diflerential.

It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. An auxiliary control mechanism for hydraulic classifiers comprising, in combination, a tank having an overflow and a valved underflow outlet; said underflow outlet being comprised of an opening enclosed by a downwardly slanting duct; said opening providing a first seat; a discharge mechanism having a valve in seating relation with said seat, and controlling egress therethrough; said duct providing a second seat at the lower end thereof; a weightresponsive gate engaging said second seat; said gate connected to' a receptacle disposed below and alignedwith the open end of said duct; said receptacle having an adjustably restrictive outlet in the bottom thereof; the upper edge of said receptacle being in spaced relation to the outermost and lower edge of said duct; the upper edge of said receptacle, and the lower edge of said duct conjunctively providing a passage therebetween for regularly discharging underflow; the upper edge of said receptacle providing a pre-determined limit; said limit being related to the trajectory path of regularly discharging underflow; said gate co-acting with excessively trajecting underflow accumulating within said receptacle, whereby the discharging of classifier content is intercepted by closing said second opening for a pre-determined length of time.

2. In a material discharge valve structure comprising, in combination, a tank and a float chamber; said tank having an overflow and an underflow outlet; said float chamber having a sloping bottom, and being positioned outside of said tank; a drain pipe in said float chamber;

umbrella means having a lower edge, an underside and an upper surface, and being positioned intermediate of overflow and underflow outlets to provide a predetermined material level by the horizontal plane of said edge; communication means associated with said tank and said float chamber to provide communication therebetween; said communication means being comprised of an opening and said float chamber bottom to conjunctively provide a downwardly inclined passageway for the heavier of two media, and an upwardly inclined course with respect to liquid communication between said tank and said float chamber; said opening being disposed intermediate of the lower edge and the upper surface of said umbrella means; said umbrella means providing a distribution zone comprised of the open space between the underside of said umbrella means, and the surface of the material therebelow; a classifying zone extending upwardly of the plane of said edge; a recovery zone extending downwardly therefrom; said zones in open communication with one another; said lower edge co-operatively related with material in the tank to variably restrict flow into the float chamber; a valve stem; connecting means associated with said valve stem and said float; a pipe member co-axially mounted to said valve stem and providing a housing for same; an adjustable stop engaging said valve stem above the tank; a discharge valve adapted to close said underflow outlet; said valve being connected to said valve stem, and thereby actuated by variation of the fluid level in the float chamber, and by variation of the material level in the tank; an auxiliary inlet means providing controlled communication between said tank and said float chamber; and a vent pipe extending upwardly of said umbrella means.

3. An auxiliary control mechanism for hydraulic classifiers comprising, in combination, a tank having an overflow and a valved underflow outlet; said underflow outlet being comprised of an opening in said tank, and a discharge pipe surrounded by a suspended and automatically positioning sleeve; a discharge mechanism having a valve in seating relation with said discharge pipe, and controlling egress therethrough; said valve being in seating relation with said sleeve and being oversized to thereby provide a seat for said sleeve; said sleeve being fastened to an annular receptacle; said receptacle being comprised of an inner, open-ended cylinder, an outer cylinder, and a sloping bottom therebetween leading to adjustably restrictive outlets controlling the rate of egress therethrough; said open-ended cylinder disposed below said discharge pipe, and providing a passage for regularly discharging underflow; said annular receptacle disposed to confine underflow trajecting over the upper edge of said inner cylinder, and positioned co-axially with said valve; and weight responsive means co-operative with material trajecting into the annular receptacle.

4. In an auxiliary control mechanism for hydraulic classifiers such as described in claim 3 wherein said valve supports a cylindrical, open-ended ring arranged in spaced relation thereto.

5. In a hydraulic classifying apparatus comprising, in combination, a tank and a float chamber; said tank having an overflow and an underflow outlet; said float chamber having a sloping bottom, and being positioned on the outside of said tank; a drain pipe in said float chamber; umbrella means having a lower edge, an underside and an upper surface, and being positioned intermediate of said overflow and said underflow outlets to provide a predetermined material level by the horizontal plane of said edge; communication means associated with said tank and said float chamber to provide communication therebetween; said latter means including an opening disposed above the plane of said edge and below the upper surface of said umbrella means; said communication means providing a downwardly inclined passageway for the heavier of two media, and an upwardly inclined course for the lighter and substantially liquid medium; said umbrella means providing a distribution zone comprised of the open space between the underside of said means, and the surface of the material directly therebelow; a classifying zone extending upwardly of the plane of said edge; a recovery zone extending downwardly therefrom; said zones in open communication with one another; said lower edge co-operatively related with material in the tank to variably restrict flow into the float chamber; a float within the float chamber; discharge means adapted to control egress through said underflow outlet in association with said float; and said discharge means actuated by variation of the fluid level in the float chamber, and by variation of the material level in the tank.

6. In a hydraulic classifying apparatus such as described in claim wherein said communication means is I comprised of an inclined conduit penetrating at least to the underside of said umbrella means.

7. In a hydraulic classifying apparatus such as described in claim 5 wherein said discharge means is provided with an externally positioned valve control comprised of said float; a lever pivotally connected to said float in said float chamber, and extending across the top of said tank to and beyond the wall opposite to said float chamber; a beam having brackets and resting against the upper edge of said tank to provide support for said lever; said lever having a forked end to pivotally engage a downwardly extending rod, and being pivoted about a pin through said brackets; said rod pivotally connected to the outwardly extending arm of a pivoted bell crank disposed intermediate of said rod and the outside of said tank, and fastened thereto above said underflow outlet; a valve fastened to the downwardly extending arm of said bell crank; said valve in seating relation with said underflow outlet; said float being responsive to variations of the fluid level in the float chamber and to variations of the material level in the tank, whereby said float will open and close said underflow outlet.

8. The structure as set forth in claim 5 wherein said umbrella means is horizontally disposed and wherein said communication means comprises an inclined conduit having an opening provided below said horizontally disposed umbrella means.

9. The structure as set forth in claim 5 wherein said umbrella means is inclined and wherein said communication means includes an opening disposed below said inclined umbrella means.

10. In a hydraulic classifying apparatus such as described in claim 5 wherein said umbrella means is comprised of an apertured partition extending between the walls of said tank having an open-ended cylinder extending downwardly therefrom providing said lower edge and a vertically oriented passage, and wherein said communication means includes a sloping conduit extending upwardly of said opening below the surface of said umbrella means.

11. In a material discharge valve structure for classifying materials of varying densities, the combination comprised of a tank and a float chamber; said tank having an overflow and an underflow outlet; said float chamber having a sloping bottom and being positioned outside of said tank; a drain pipe in said float chamber; umbrella means positioned intermediately of said overflow and underflow outlets; said umbrella means including an underside and a lower edge; the latter providing a predetermined material level defined by the horizontal plane of said lower edge; a distribution zone comprised of the open space between said underside of said umbrella means and the surface of the material below said umbrella means; communication means connecting said tank and said float chamber; said latter means providing a downwardly inclined passageway for material having the greater density and an upwardly inclined course affording liquid communication between said tank and said float chamber; a classifying zone extending upwardly of the plane of said lower edge; a recovery zone extending downwardly from said lower edge; said zones being communicably arranged; said lower edge being adapted to coact with material in said tank to variably restrict flow into said float chamber; a valve stem; connecting means associated with said valve stem and said float chamber; a pipe member coaxially mounted on said valve stem and providing a housing therefor; an adjustable stop engaging said valve stem above the tank; a discharge valve adapted to close said underflow outlet; said valve stem being connected to said discharge valve; the latter being actuated by variation of the fluid level in the float chamber and by variation of the material level in the tank; an auxiliary inlet means providing controlled communication between said tank and said float chamber; and a vent pipe extending upwardly of said umbrella means.

12. In a material discharge valve structure such as described in claim 11 where said auxiliary inlet means is comprised of a segmented pipe communicating between said tank and said float chamber; an arm pivotally connected to said float, an end of said arm being disposed above the segmented pipe; an auxiliary valve suspended by flexible means from said arm in removable,

seating relation with said segmented pipe, whereby the raising or lowering of the float will open or close the intake end of said pipe by said auxiliary valve.

13. In a material discharge valve structure such as described in claim 11 wherein said coaxially mounted pipe member is suspended from a beam resting against the upper edge of said tank; said pipe being open at the upper end, and extending downwardly into said tank; a sealhousing carrying a seal secured to the lower end of said pipe; and said seal engaging said valve stem above said discharge valve.

14. In a material discharge valve structure such as described in claim 11 wherein said coaxially mounted pipe member is suspended from a beam placed across the top of said tank; said pipe extending downwardly into said tank to above said discharge valve; a hydraulic seal fitting secured to said pipe at the lower end thereof; the upper end of said pipe extending above said beam; a sealhousing enclosing a seal secure to the upper end of said pipe; said seal engaging said valve stem above said beam; and a valved branch pipe connecting with said pipe member below said seal-housing.

15. In a material discharge valve structure such as described in claim 11 wherein said connecting means comprise a system of levers fulcrumed above and supported by a beam placed across the top of said tank; said system of levers adapted to pivotally engage said valve stem and said float, whereby said discharge valve will move in the same direction as said float.

' 16. In a material discharge valve structure such as described in claim 11 wherein said valve stem is comprised of a pipe.

17. The structure as set forth in claim 11 wherein said umbrella means is horizontally disposed and wherein said communication means comprises an inclined conduit having an opening provided below said horizontally disposed umbrella means.

18. The structure as set forth in claim 11 wherein said umbrella means is inclined and wherein said communication means includes an opening disposed below said inclined umbrella means.

19. A hydraulic classifying apparatus comprising, in combination, a tank and a float chamber; said tank having upper and lower ends and being formed of upper and lower portions, said upper portion having substantially vertical walls; said lower portion having inclined walls generally converging at the lower end of said tank; said float chamber being disposed adjacently with respect to said upper portion; umbrella means being positioned intermediate of said upper and lower ends; said umbrella means having a platform surface disposed substantially normally with respect to the inside walls of said upper References Cited UNITED STATES PATENTS 2,476,131 7/1949 Breyfogle 210123 2,999,594 9/1961 Thamme 209496 X 3,034,647 5/1962 Giesse 209211 X 3,077,265 2/1963 Thamme 209-496 X FRANK W. LUTTER, Primary Examiner. 

1. AN AUXILIARY CONTROL MECHANISM FOR HYDRAULIC CLASSIFIERS COMPRISING, IN COMBINATION, A TANK HAVING AN OVERFLOW AND A VALVED UNDERFLOW OUTLET; SAID UNDERFLOW OUTLET BEING COMPRISED OF AN OPENING ENCLOSED BY A DOWNWARDLY SLANTING DUCT; SAID OPENING PROVIDING A FIRST SEAT; A DISCHARGE MECHANISM HAVING A VALVE IN SEATING RELATION WITH SAID SEAT, AND CONTROLLING EGRESS THERETHROUGH; SAID DUCT PROVIDING A SECOND SEAT AT THE LOWER END THEREOF; A WEIGHTRESPONSIVE GATE ENGAGING SAID SECOND SEAT; SAID GATE CONNECTED TO A RECEPTACLE DISPOSED BELOW AND ALIGNED WITH THE OPEN END OF SAID DUCT; SAID RECEPTACLE HAVING AN ADJUSTABLY RESTRICTIVE OUTLET IN THE BOTTOM THEREOF; THE UPPER EDGE OF SAID RECEPTACLE BEING IN SPACED RELATION TO THE OUTERMOST AND LOWER EDGE OF SAID DUCT; THE UPPER EDGE OF SAID RECEPTACLE, AND THE LOWER EDGE OF SAID DUCT CONJUNCTIVELY PROVIDING A PASSAGE THEREBETWEEN FOR REGULARLY DISCHARGEING UNDERFLOW; THE UPPER EDGE OF SAID RECEPTACLE PROVIDING A PRE-DETERMINED LIMIT; SAID LIMIT BEING RELATED TO THE TRAJECTORY PATH OF REGULARLY DISCHARGING UNDERFLOW; SAID GATE CO-ACTING WITH EXCESSIVELY TRAJECTING UNDERFLOW 